2003 CHEVROLET EXPRESS CARGO VAN trailer

qRotate tires. SeeTire Inspection and Rotation on
page 5-58for proper rotation pattern and additional
information.(See footnote +.)
97,500 Miles (162 500 km)
qCheck rear/front axle ¯uid level and add ¯uid as
needed. Check constant velocity joints and axle seals
for leaking.
qRotate tires. See
Tire Inspection and Rotation on
page 5-58for proper rotation pattern and additional
information.(See footnote +.)
100,000 Miles (166 000 km)
qInspect spark plug wires.An Emission Control
Service.
qReplace spark plugs.An Emission Control Service.
qChange automatic transmission ¯uid and ®lter if
the vehicle's GVWR is over 8600 lbs or if the vehicle
is mainly driven under one or more of these
conditions:
þ In heavy city traffic where the outside
temperature regularly reaches 90ÉF (32ÉC) or
higher.þ In hilly or mountainous terrain.
þ When doing frequent trailer towing.
þ Uses such as found in taxi, police or delivery
service.
qIf you haven't used your vehicle under severe service
conditions listed previously and, therefore, haven't
changed your automatic transmission ¯uid, change
both the ¯uid and ®lter.
qInspect Positive Crankcase Ventilation (PCV) valve.
An Emission Control Service.
150,000 Miles (240 000 km)
qDrain, ¯ush and re®ll cooling system (or every
60 months since last service, whichever occurs ®rst).
See
Engine Coolant on page 5-21for what to use.
Inspect hoses. Clean radiator, condenser, pressure
cap and neck. Pressure test the cooling system
and pressure cap.
An Emission Control Service.
qInspect engine accessory drive belt.An Emission
Control Service.
6-10

When to Change Engine Oil
If any one of these are true for you, use the short
trip/city maintenance schedule:
·Most trips are less than 5 miles (8 km). This is
particularly important when outside temperatures
are below freezing.
·Most trips include extensive idling (such as frequent
driving in stop-and-go traffic).
·You frequently tow a trailer or use a carrier on top
of your vehicle.
·The vehicle is used for delivery service, police, taxi
or other commercial application.
Driving under these conditions causes engine oil to
break down sooner. If any one of these is true for your
vehicle, then you need to change your oil and ®lter
every 3,000 miles (5 000 km) or 3 months Ð whichever
occurs ®rst.
If none of them is true, use the long trip/highway
maintenance schedule. Change the oil and ®lter every
7,500 miles (12 500 km) or 12 months Ð whichever
occurs ®rst. Driving a vehicle with a fully warmed engine
under highway conditions will cause engine oil to
break down slower.
How to Reset the CHANGE ENGINE
OIL Light
The GM Oil Life System calculates when to change
your engine oil and ®lter based on vehicle use. Anytime
your oil is changed, reset the system so it can
calculate when the next oil change is required. If a
situation occurs where you change your oil prior to a
CHANGE ENGINE OIL light being turned on, reset the
system.
To reset the CHANGE ENGINE OIL light, do the
following:
1. Turn the ignition key to RUN with the engine off.
2. Fully press and release the accelerator pedal
three times within ®ve seconds.
3. If the CHANGE ENGINE OIL light ¯ashes for ®ve
seconds, the system is reset.
If the system does not reset, try the procedure once
again. If it still does not reset, see your dealer for
service.
See
Change Engine Oil Light on page 3-37.
5-16

Automatic Transmission Fluid
When to Check and Change
A good time to check your automatic transmission ¯uid
level is when the engine oil is changed.
Change both the ¯uid and ®lter every 50,000 miles
(83,000 km) if the vehicle's GVWR is over 8,600 or if
the vehicle is mainly driven under one or more of these
conditions:
·In heavy city traffic where the outside temperature
regularly reaches 90ÉF (32ÉC) or higher.
·In hilly or mountainous terrain.
·When doing frequent trailer towing.
·Uses such as found in taxi, police or delivery
service.
If your vehicle's GVWR is not over 8,600 and you do
not use your vehicle under any of these conditions,
change the ¯uid and ®lter every 100,000 miles
(166 000 km).
See
Part A: Scheduled Maintenance Services on
page 6-4.
How to Check
Because this operation can be a little difficult, you may
choose to have this done at the dealership service
department.
If you do it yourself, be sure to follow all the instructions
here, or you could get a false reading on the dipstick.
Notice:Too much or too little ¯uid can damage
your transmission. Too much can mean that some
of the ¯uid could come out and fall on hot engine
part or exhaust system parts, starting a ®re.
Too little ¯uid could cause the transmission to
overheat. Be sure to get an accurate reading if you
check your transmission ¯uid.
Wait at least 30 minutes before checking the
transmission ¯uid level if you have been driving:
·When outside temperatures are above 90ÉF (32ÉC).
·At high speed for quite a while.
·In heavy traffic ± especially in hot weather.
·While pulling a trailer.
To get the right reading, the ¯uid should be at
normal operating temperature, which is 180ÉF to 200ÉF
(82ÉC to 93ÉC).
5-19

{CAUTION:
Steam from an overheated engine can burn
you badly, even if you just open the hood.
Stay away from the engine if you see or hear
steam coming from it. Just turn it off and get
everyone away from the vehicle until it cools
down. Wait until there is no sign of steam or
coolant before you open the hood.
If you keep driving when your engine is
overheated, the liquids in it can catch ®re. You
or others could be badly burned. Stop your
engine if it overheats, and get out of the
vehicle until the engine is cool.
See ªOverheated Engine Protection Operating
Modeº in the Index for information on driving
to a safe place in an emergency.
Notice:If your engine catches ®re because you
keep driving with no coolant, your vehicle can
be badly damaged. The costly repairs would
not be covered by your warranty.See ªOverheated Engine Protection Operating
Modeº in the Index for information on driving
to a safe place in an emergency.
If No Steam Is Coming From Your
Engine
If you get an engine overheat warning but see or hear
no steam, the problem may not be too serious.
Sometimes the engine can get a little too hot when you:
·Climb a long hill on a hot day.
·Stop after high-speed driving.
·Idle for long periods in traffic.
·Tow a trailer. See ªDriving on Gradesº inTowing a
Trailer on page 4-31
.
If you get the overheat warning with no sign of steam,
try this for a minute or so:
1. In heavy traffic, let the engine idle in NEUTRAL(N)
while stopped. If it is safe to do so, pull off the road,
shift to PARK (P) or NEUTRAL(N) and let the
engine idle.
2. Turn on your heater to full hot at the highest fan
speed and open the window as necessary.
5-25

Engine Fan Noise
Your vehicle has a clutched engine cooling fan. When
the clutch is engaged, the fan spins faster to provide
more air to cool the engine. In most everyday driving
conditions, the fan is spinning slower and the clutch is
not fully engaged. This improves fuel economy and
reduces fan noise. Under heavy vehicle loading, trailer
towing and/or high outside temperatures, the fan
speed increases as the clutch more fully engages. So
you may hear an increase in fan noise. This is
normal and should not be mistaken as the transmission
slipping or making extra shifts. It is merely the cooling
system functioning properly. The fan will slow down
when additional cooling is not required and the clutch
partially disengages.
You may also hear this fan noise when you start the
engine. It will go away as the fan clutch partially
disengages.
Power Steering Fluid
The power steering ¯uid reservoir is located in the
engine compartment on the driver's side of the vehicle.
5-34

Fuse Usage
1 Spare
2 Outside Rear View Mirror
3 Courtesy Lamp/SEO
4 Left Rear Stop/Turn Signal
5 Cargo Locks
6 Right Rear Stop/Turn Signal
7 Driver Locks
8Stop/Center High Mounted Stop
Lamp
9 Climate Control 1
10 Climate Control
11 Brakes
12 Heated Mirror/Defogger
13 Right Rear Blower
14 Driver Turn Mirror
15 Door Locks
16 Up®tter Park
17 Not Available
18 Left Rear Park LampFuse Usage
19 Pass Turn Mirror
20 Right Rear Park Lamp
21 Trailer Park Lamp
22 Front Park Lamp
32 Auxilary1
33 Auxilary2
Relays Usage
23 Window Residual Accessory Power
24 Auxiliary
25 Right Rear Defogger
26 Courtesy Lamp
27 Cargo Unlock
28 Driver Unlock
29 Park Lamp
30 Door Locks
31 Pass Unlock
Circuit Breaker Usage
34 Power Window
5-93

Fuse Usage
1 Radio Battery
2 Powertrain Control Module Battery
3 Left Rear Turn Lamp
4 Right Rear Turn Lamp
5 Backup Lamps Trailer Wiring
6 Ignition 0
7 Stop Lamp
8 Right Rear Defogger/Heated Mirror
9Right Daytime Running Lamp/Turn
Signal
10Left Daytime Running Lamp/Turn
Signal
11 Truck Body Control Module 4
12 Fuel Pump
13 Trailer
14 Flasher
15 Horn
16 Truck Body Control Module 3
17 Trailer Stop/Turn Signal
18 Truck Body Control Module 2
19 Truck Body Control Module
20 Remote Function Actuator
21 Engine 2Fuse Usage
22 Ignition E
23 Engine 1
24Truck Body Control Module
Ignition 1
25 Spare
26 RPA/Inside Rearview Mirror
27 Crankcase
28Brake Transmission Shift Interlock
System
29 Auxiliary Power Outlets
30 Cigarette Lighter
31 Instrument Panel Cluster
32 Air Conditioning
33 Spare
34 Vent
35 Spare
36 Vehicle Back Up
37Supplemental In¯atable Restraint
System
38 Powertrain Control Module Ignition 1
39 Oxygen Sensor B
40 Oxygen Sensor A
41 Windshield Wipers
5-95

Fuse Usage
42 Right Headlamp Ð Low Beam
43 Left Headlamp Ð Low Beam
44 Left Headlamp Ð High Beam
45 Right Headlamp Ð High Beam
46Truck Body Control
Module-Accessory
47 Front Windshield Wiper
48 Anti-Lock Brakes
49 Ignition A
50 Trailer
51 Climate Control Blower
52 Ignition B
63 Spare
64 SpareFuse Usage
Relay Usage
53 Windshield Wiper
54 Air Conditioning
55 Spare
56 Headlamp Ð High Beam
57 Fuel Pump
58 Headlamp Ð Low Beam
59 Horn
61 Starter
62 Spare
Circuit Breaker Usage
60 Power Seat
5-96